Redundant Arrays of Independent Disks (RAID) technology is implemented in mass storage of data. A RAID array is a logical structure including multiple RAID disks that work together to improve storage reliability and performance. One implementation of a RAID technique implements a mirrored array of disks whose aggregate capacity is equal to that of the smallest of its member disks. Another implementation of a RAID technique implements a striped array whose aggregate capacity is approximately the sum of the capacities of its members. RAID technology can provide benefits compared to individual disks such as improved I/O performance due to load balancing, improved data reliability, improved storage management.
Several classifications or levels of RAID are known—RAID 0, RAID 1, RAID 5, and RAID 6. Certain RAID arrays, for example, RAID 1, RAID 5, RAID 6, implement added computations for fault tolerance by calculating the data into drives and storing the results in another drive. The parity is computed by an exclusive OR Boolean operation (XOR). When a drive fails, the data in the drive that has failed can be recovered from the other drives using the computed parity so that the recovered data can be written to a replacement drive.